Tenant asking what kind of dog to get

[Bob Drew]

I usually have a no pet policy. I liked a young couple who saw the house and agreed to be open to them getting a dog as a pet in the future. 

Now they are asking me what dog breed is acceptable. They are willing to work with me. My understanding is that a smaller dog (weight restrictions?) is of lower maintenance and preferred from a landlord perspective. Thoughts on what I should tell them as an acceptable "dog list"?

Also I'll be charging additional pet rent a deposit. How much should I be charging and should I amend the current lease? 

Thanks in advance.